A load cell mass comparator is disclosed in applicants' U.S. Pat. No. 4,523,653 wherein a load cell is employed in a comparator assembly wherein comparisons between a standard and applied weights are obtained by suspending the weights from the assembly. To minimize hysterisis and creep error in the load cell, variations of stress on the strain gages within the load cell are minimized by applying a preload, such as a tension on the load cell at all times, even during weight exchanges. The comparator assembly is also constructed and arranged to maintain an axial alignment between the load cell and the mass to be calibrated.
In applicants' continuing research and development in the field of load cell mass comparators, the concept of preloading the load cell to minimize hysterisis and creep error has now been extended to top loading cell mass comparators.
While top loading weighing apparatus has been proposed having load cells operatively connected to a weight supporting platform, as disclosed in U.S. Pat. Nos. 3,993,150 and 4,411,327, the concept of preloading the load cells has not been considered.